glochidium

mollusk larva

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Last updated

June 29, 2026

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A glochidium is the larval stage of freshwater mussels belonging to the family Unionidae. These larvae are characterized by hook-like appendages, which they use to attach themselves to fish as a temporary external parasite. This parasitic phase is crucial for the glochidium's development, allowing it to eventually detach and metamorphose into an adult mussel on the lake floor. The term "glochidium" itself originates from Greek words meaning "projecting point," referring to these larval hooks.12

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bivalve
Reproduction and life cycles
… the released larva, called a glochidium, often has sharp spines projecting inward from each valve. The larva attaches to either the gills or fins of passing fish and becomes a temporary parasite. Eventually, it leaves the fish, falls to the lake floor, and metamorphoses into an adult.
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… the released larva, called a glochidium, often has sharp spines projecting inward from each valve. The larva attaches to either the gills or fins of passing fish and becomes a temporary parasite. Eventually, it leaves the fish, falls to the lake floor, and metamorphoses into an adult.
Read More